Could be related to some of the nfs bugs that have been noted already
with rhel5. make sure your kernel is 2.6.18-53.1.4

-----Original Message-----
From: rhelv5-list-bounces@(protected)
[mailto:rhelv5-list-bounces@(protected)
Tinivelli
Sent: Tuesday, January 29, 2008 11:09 AM
To: rhelv5-list@(protected)
Subject: [rhelv5-list] Problem with NFS on new rhel5 kernels

Hi all,

i've experiencing a problem difficult to solve about NFS performance.

I have a web server cluster (running on RHEL4) where all servers mount a

nfs file server (NetApp F270):

[root@(protected)
fil01:/vol/vol1/web /www nfs
rw,v3,rsize=8192,wsize=8192,hard,intr,tcp,nolock,proto=tcp,timeo=4,retra
ns=5,addr=fil01
0 0

Mounting the file server on a new machine where is running a fresh
install of RHEL5 (don't care about sizes, i have tried all combination
possible)

[root@(protected)
fil01:/vol/vol1/web /www nfs
rw,vers=3,rsize=32768,wsize=32768,hard,intr,nolock,proto=tcp,timeo=4,ret
rans=5,sec=sys,addr=fil01
0 0

shows a performance problem: the CPU load and ops/s on the NetApp
increase dramatically, and reading becomes slow

nfsstat command shows an interesting fact: a very high number of lookups

Client nfs v3:
null      getattr    setattr    lookup     access
0      0% 10366   0% 2      0% 975623  90% 63084

at the moment I have some "nested mounting" (a second file server
mounted on a directory in the filesystem of the main one) and i'm moving

them in a non "nested" way.

Is this a possibile cause of the problem? What other can i try?

Thank you in advance

--
Alessandro Tinivelli
alessandro.tinivelli@(protected)

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